The present invention is directed to a strapping machine refeed system. More particularly, the present invention is directed to a centrifugal boost wheel in a strapping machine refeed system to refeed strap following a strap error or fault.
Strapping machines are well known in the art for securing straps around loads. One type of known strapper is a stationary unit that includes a strapping head or weld head and drive mechanism mounted within a frame. A chute is mounted to the frame, through which the strapping material is fed. In a typical arrangement, a table-top or work surface is likewise mounted to the frame.
In a typical stationary strapper, the chute is mounted from about the work surface, and the strapping head is mounted below the work surface. Strap is fed from a source or dispenser to the strapping or weld head. The strapping head provides a number of functions. First, it provides structure to grip portions of the strap during the course of a strapping operation. The strapping head also includes a cutter to cut the strap from a strap source or supply. Last, the strapping head includes a sealer to seal an overlying course of strapping material onto itself. This seal is commonly referred to as a weld and is effected by heating overlying courses of the strap by use of a vibrating element or a heated element.
The feed system includes a pair of feed and tensioning or retraction wheels to feed the strap through the strapping head and chute and back to the strapping head, to pull the strap from the chute to around the load and to tension the strap around the load. The strapping machine can also include a winder or tensioning element to “pull” a greater tension in the strap. Typically, the winder is positioned in the feed system.
To permit efficient operation of the strapping machine and the overall strapping process, the strapping machine can be fully automated or substantially fully automated.
In the event a strap error occurs, the faulted strap is ejected from the feed system. In order reduce required operator attention, an automatic refeed is used to refeed the strap to the strapping head (to the feed wheels). Known automatic refeed systems include complex arrangement having a pair of rotating elements, one of which pivots toward and away from the other depending upon the presence or absence of strap between the elements. While these known systems function well, in order to maintain the systems optimally functioning, significant set-up and maintenance is required. In addition, when the strapping machine is operating in a mode in which high tension is required, the strap is pulled around the re-feed element, thus necessitating a relatively complex strap path arrangement.
Accordingly, there is a need for a strapping machine having a strap feeding and tensioning system with automatic refeed of the strap material. Desirably, such a system automatically refeeds the strap into the strapping head using elements that can remain present in the strap path during normal strapping operation.